通过post方法返回的Webrequest 404没有找到

Question

像tittle说的，我试图通过发布到某个页面发出请求。首先使用谷歌开发人员工具，检查参数的请求，我可以弄清楚这一点（我不完全确定是否将所有正确的参数放在我的后字符串中 - 查看图像以获取更多信息）。我在www的网站上发现了很多例子，但是没有人能够使用这个例子，我不知道什么是错误的，我总是会有点帮助:)。

请求头

表单数据

这是我的代码：

string email = "xxxxx"; 
string password = "xxxxx"; 

string LOGIN_URL = "https://intranet.cibertec.edu.pe/LoginBolsa/LoginBolsaCIB.aspx"; 

CookieContainer cookies = new CookieContainer(); 

HttpWebRequest webRequest = WebRequest.Create(LOGIN_URL) as HttpWebRequest; 
webRequest.CookieContainer = cookies; 
StreamReader responseReader = new StreamReader(
     webRequest.GetResponse().GetResponseStream() 
    ); 
string responseData = responseReader.ReadToEnd(); 
responseReader.Close(); 

string postString = string.Format("ctl00$ContentPlaceHolder1$Login1$UserName={0}&ctl00$ContentPlaceHolder1$Login1$Password={1}&ctl00$ContentPlaceHolder1$Login1$LoginButton={2}&hdnOrigen={3}&hdnLinea={4}&Pagina_Principal={5}", email, password, "Ingresar", "bolsa", "I", "LoginBolsaCIB.aspx"); 


webRequest = WebRequest.Create(LOGIN_URL) as HttpWebRequest; 
webRequest.Method = "POST"; 
webRequest.ContentType = "application/x-www-form-urlencoded"; 
webRequest.CookieContainer = cookies; 


StreamWriter requestWriter = new StreamWriter(webRequest.GetRequestStream()); 
requestWriter.Write(postString); 
requestWriter.Close(); 

responseReader = new StreamReader(webRequest.GetResponse().GetResponseStream()); 
responseData = responseReader.ReadToEnd(); 
responseReader.Close(); 

Response.Write(responseData); 

Answer 1

这是因为缺少__ViewState参数。这个参数是隐藏表单域需要附加每个请求。

int start = responseData.IndexOf("value=\"", responseData.IndexOf("name=\"__VIEWSTATE\"")); 
int end = responseData.IndexOf("/>", start); 
string viewState = responseData.Substring(start + 7, end - start - 9); 
string postString = string.Format("ctl00$ContentPlaceHolder1$Login1$UserName={0}&ctl00$ContentPlaceHolder1$Login1$Password={1}&ctl00$ContentPlaceHolder1$Login1$LoginButton={2}&hdnOrigen={3}&hdnLinea={4}&Pagina_Principal={5}", email, password, "Ingresar", "bolsa", "I", "LoginBolsaCIB.aspx"); 
postString += String.Concat("&__VIEWSTATE=", viewState);